Author:

Abstract

Introduction: A comprehensive evaluation to identify metabolic abnormalities will help design management strategies for prevention of renal stone recurrences. The objective of this study is to identify the metabolic risk factors in a series of patients with recurrent, multiple or bilateral renal stone disease from the Northern Province, Sri Lanka.

Methods: This is a hospital based observational study on patients with recurrent, multiple or bilateral renal stones. Metabolic evaluation workout included, fasting non-tourniquet venous blood sample for serum ionized calcium, creatinine, and uric acid, freshly voided early morning urine sample for pH and laboratory urinalysis, and collection of two sets of 24 hour urine samples on two separate days, for phosphorous, creatinine, oxalate, uric acid, magnesium, calcium and citrate.

Results: The mean values of each metabolic parameter measured on the two sets of 24 hour urine samples, were found to be within the normal reference range for the entire 30 patient study group taken as whole, although the mean values for 24 hour urine magnesium (79.79±51.36 mg) and urine calcium (125.02±73.32 mg) were found to be towards the lower limit of normal reference range and the 24 hour urine oxalate (0.38±0.22 mmol) was found to be towards the upper limit of normal reference range. However, 80% of patients individually showed abnormal metabolic results either as single derangement (13 patients, 43.3%) or in multiple combinations of derangements (11 patients, 36.7%). Six patients (20%) did not have any metabolic abnormalities. Hyperoxaluria, hyperuricosuria, hypomagnesuria and hypocitraturia were the metabolic abnormalities identified among the study group.

Conclusion: A comprehensive metabolic evaluation of each patient with recurrent, multiple or bilateral renal stone disease can help identify metabolic abnormalities, either as a single abnormality or combinations of abnormalities, specific for them.  Such patient profiling will help develop bespoke management strategy based on appropriate dietary advice and specific medical treatment towards prevention of further stone formation.

Keywords: Metabolic evaluation, Nephrolithiasis, Recurrent and multiple or bilateral renal stone formers